Download The Epidemiology Triangle

The Epidemiologic Triangle
Time
The Epidemiologic Triangle
• The agent is the cause of the disease
– Can be bacteria, virus, parasite, fungus, mold
– Chemicals (solvents), Radiation, heat, natural toxins
(snake or spider venom)
• The host is an organism, usually human or
animal, that harbors the disease
• Pathogen disease-causing microorganism or
related substance
– Offers subsistence and lodging for a pathogen
– Level of immunity, genetic make-up, state of health,
and overall fitness within the host can determine the
effect of a disease organism can have upon it.
The Epidemiologic Triangle
• The environment is the favorable surroundings
and conditions external to the human or animal
that cause or allow the disease or allow disease
transmission
– Environmental factors can include the biological
aspects as well as the social, cultural, and physical
aspects of the environment
• Time accounts for incubation periods, life
expectancy of the host or pathogen, duration of
the course of illness or condition.
The Epidemiologic Triangle
• The mission of the epidemiologist is to break one of the
legs of the triangle, which disrupts the connection
between environment, host, and agent, stopping the
continuation of an outbreak.
• The goals of public health are the control and prevention
of disease.
• By breaking one of the legs of the triangle, public health
intervention can partially realize these goals and stop
epidemics
• An epidemic can be stopped when one of the elements
of the triangle is interfered with, altered, changed or
removed from existence.